Unit for the regulation or control of a fluid pressure

ABSTRACT

A unit ( 10 ) for the regulation or control of a fluid pressure, having at least one housing section ( 13, 14 ) and a switching film ( 22 ) connected to the at least one housing section ( 13, 14 ) for switching at pressure differentials relative to an ambient pressure acting on the switching film ( 22 ), and for the regulation, release or blocking of a flow of the fluid between an inlet ( 28 ) and a discharge ( 30 ) for the fluid. The switching film ( 22 ) is made out of a polymer material having fluorine and carbon, in particular a thermoplastic having fluorine and carbon. In this arrangement, a hole cross-section ( 40 ) of the at least one housing section ( 13, 14 ) is closed off by the switching film ( 22 ).

TECHNICAL FIELD

The invention relates to a unit for the regulation or control of a fluidpressure, in particular for the pressure regulation of an internalcombustion engine and/or of the crankcase of the internal combustionengine of a motor vehicle and a method for fluid-tight connection of aswitching film to at least one housing section of the unit.

BACKGROUND

Pressure regulating valves are used, for example, in the breather linebetween crankcase and the intake manifold of an internal combustionengine. This involves not allowing the pressure or vacuum in thereceptacles to be vented to increase beyond a predetermined value.

In internal combustion engines, blow-by gases occur that are produced bycombustion gases in the cylinder getting past the cylinder piston intothe crankcase. These blow-by gases allow the pressure in the crankcaseto rise, whereby leaks and spillages of oil can be the result. In orderto prevent a pressure increase and to discharge these blow-by gases inan environmentally friendly manner, these are conducted from thecrankcase back into the air feeder line of the internal combustionengine. Furthermore, the specified negative pressure value should not besignificantly undershot, because otherwise undesired air can beerroneously sucked into the crankcase.

In the pressure regulating valves that are currently being used, anelement familiar to a person skilled in the art under the term“switching membrane” made from elastomer, commonly fluorosilicone rubberis generally employed. These switching membranes are very flexiblebecause of the specific properties of elastomers. Depending on theapplied pressure ratios, this switching membrane opens or closes anopening in the pressure regulating valve. The pressure ratio generallyresults from the pressure differential between the applied pressure in afirst chamber and the pressure prevailing in a second chamber of thepressure regulating valve. The pressure in the first chamber may forexample be the same as the atmospheric pressure. The switching membranemust react to low switching pressures on the order of 1 to 250 mbar.

Blow-by gases in an internal combustion engine are made up of unburnedfuel components, motor oil components and other pollutants resultingfrom the combustion. These gases attack many elastomer types, wherebydamages to the material properties can occur. The components made fromthese materials become brittle, porous and cracked. If the switchingfilms are damaged, the environmentally damaging blow-by gases passdirectly into the environment, because the system is no longer sealed.The switching membrane made from elastomer is generally executed as rollfilm, in order to realize a specific stroke of the switching membrane.The material in the roll region is also mechanically damaged through theunrolling motion by simultaneous contact with blow-by gases and can thusbe damaged.

The DE 26 29 621 A1 discloses a diaphragm valve having a switchingmembrane that is designed as a switching film clamped at its edgebetween the housing and the housing cover which is to be brought into asealing contact by a pressure member against a seating surface providedin the housing, wherein the switching membrane is made of a thinnerlayer of low elasticity, for example from PTFE, facing towards thehousing interior that is resistant to aggressive through-flow media, andan additional, thicker layer made of elastomeric material. Diaphragmvalves of this type are primarily used where a high chemical resistanceof the materials coming into contact with the through-flow medium isrequired.

Because elastomeric materials do not meet this requirement but thechemically resistant materials such as PTFE do not possess theelasticity necessary for a proper function, films comprising two layersare used. The contact pressure that is applied by the pressure membervia the thick, rubber-like layer is transmitted as evenly as possibleonto the sealing surface of the switching film that works together withthe seating surface in the housing. In this arrangement, relativelylarge switching pressures of several bar are exerted on the switchingmembrane for closing the two-layered switching membrane via a pressurespindle that is connected to a hand wheel in order to ensure thenecessary sealing function by the stiff PTFE layer.

SUMMARY OF THE INVENTION

It is an object of the invention to create a unit for switching at lowpressure differentials that achieves a high operational life inoperation in an internal combustion engine with aggressive media, inparticular from so-called blow-by gases

It is an additional object of the invention to create a method forfluid-tight connection of a switchable closing element to the unit, thatachieves a high operational life during operation in an internalcombustion engine having aggressive media, in particular from so-calledblow-by gases.

The aforementioned object is achieved according to one aspect of theinvention by a unit for regulation or control of a fluid pressure and ofa switching film connected to at least one housing section, wherein theswitching film is formed from a polymer film from a polymer materialhaving fluorine and carbon and wherein a hole cross-section of the atleast one housing section is closed off by the switching film. Theswitching film having fluorine and carbon can be formed in particular bya film from thermoplastic having fluorine and carbon.

According to another aspect of the invention, the additional object isachieved by a method for fluid-tight connection of a switching film toat least one housing section or a unit, wherein the switching film has aconnecting element that is connected in the area of at least one matingarea to the at least one housing section, in particular integrallyand/or interlockingly bonded, welded, or pressed.

Favorable embodiments and advantages of the invention are disclosed inthe further claims, the description and the drawings.

A unit is proposed for the regulation or control of a fluid pressure,having at least one housing section and a switching film connected tothe at least one housing section for switching at pressure differentialsof 1 to 250 mbar, preferably from 1 to 100 mbar, relative to an ambientpressure acting on the switching film, and for the regulation, releaseor blocking of a flow of the fluid between an inlet and a discharge forthe fluid, wherein the switching film is made out of a polymer materialhaving fluorine and carbon, in particular thermoplastic having fluorineand carbon, and wherein a hole cross-section of the at least one housingsection is closed off by the switching film.

The unit does not only serve to release or shut off a through-flow, butregulates between the two switching states “release” or “shut off” by acontinuous alteration of the through-flow cross-section as a function ofthe pressure differential on the through-flow of fluid between the inletand the discharge. In this manner, the through-flow can be restricted.

A polymer film having fluorine and carbon, in particular a thermoplasticfilm having fluorine and carbon, is chemically resistant and can switchmany switching cycles of the film valve. The long-term stability of theunit is improved. In particular, the polymer film having fluorine andcarbon can be PTFE (polytetrafluorethylene). Alternatively, the polymerhaving fluorine and carbon can be made of a PTFE as the base material,which has admixtures, in particular an admixture of glass fiber, glassspheres, graphite and/or carbon fibers, in particular having aproportion of the admixed substances of up to 60%; similarly, thepolymer having fluorine and carbon can be a thermoplasticallyprocessable PTFE, which is processable in a spraying process, inparticular. Preferably, the switching film is at most 0.5 mm thick,preferably at most 0.3 mm, particularly preferably at most 0.2 mm thick.The switching film can have a diameter between 40 mm and 100 mm,preferably between 50 mm and 80 mm. It is possible that withcorrespondingly large diameters somewhat higher thickness of theswitching film in the region of over 0.5 mm, for example at most 0.5 mmto 1 mm, can be realized.

A conventional switching membrane made from elastomer of a conventionalunit for pressure regulation of an internal combustion engine and/or thepressure regulation of the crankcase of an internal combustion engine isreplaced here by a switching film made from the polymer having fluorineand carbon, in particular a thermoplastic having fluorine and carbon. Apolymer material having fluorine and carbon such as PTFE can, forexample, be manufactured in a sintering process and then mechanicallyprocessed. Such a switching film in its normal form is very stiff andactually not appropriate for flexible components. PTFE has anoutstanding chemical resistance and can be used in a very broad range oftemperatures, wherein the modulus of elasticity is very sharplyincreased at low temperatures compared to elastomeric materials. Forthis reason, PTFE is not appropriate for an application as switchingfilm in the temperature range required for automotive applications in aninternal combustion engine of typically −40° C. to +150° C. Thisdisadvantage is avoided in the unit according to the invention by virtueof an advantageous geometry and optionally by an extremely thin wallthickness of the switching film made from the polymer having fluorineand carbon, in particular a thermoplastic having fluorine and carbon.

By reducing the wall thickness of the material in the switching film inan intentionally movable range of a few tenths of a millimeter, whereinthe intentionally fixed thickness range as well as the clamping regionof the material can also be executed thicker, and a specially developedgeometry of the switching film without roll region, as it isconventionally used in prior art, the stiff material is formed into ashape in which it has the necessary flexibility, but neverthelessfulfills the mechanical requirements with respect to crack formation,strain and fatigue strength under reversed bending stresses. By virtueof the special geometry, roll motion no longer takes place, rather abending motion can be realized having a radius change that can beaccomplished with low strain or even practically no strain of thematerial and with which a lifting motion of the switching film for theunit according to the invention can be implemented.

The switching film can have a plate-like flat body, in particular formedas plate-shaped flat body, having a bending region surrounding a centralsealing region, wherein the bending region moves the sealing region inan axial direction with respect to a valve seat, meaning in thedirection normal to the flat body, onto the valve seat or away from thevalve seat during switching of the switching film by alow-strain—meaning practically strain-free for practical application, inparticular strain-free—bending motion. Because the switching film inthis embodiment can flex not only in a small surface region, but broadlybecause of the plate-like shape, individual regions of the switchingfilm are hardly or practically not at all strained. The bending motionis thus executed across a large region of the switching film—and,consequently, with little elastic deformation—in the form of a curvaturechange with low strain, for example less than 10%.

The sealing region of the switching film can interrupt the through-flowof the fluid between the inlet and the discharge. The switching filmcan, for example, be located with its sealing region against a seal seatin order to interrupt the through-flow.

For this purpose, the switching film can be movable between itsrespective maximum positions in the opened and closed state byapplication of atmospheric pressure as control pressure on one side ofthe switching film. Advantageously, the switching film can beselfregulating and the switching film can be closed indirectly via apressure differential between atmospheric pressure in the one chamber ofthe unit and an operating pressure of the other chamber of the unit. Theoperating pressure can, for example, be a pressure in a crankcase of aninternal combustion engine.

Advantageously, the switching film can alternatively be movable betweenits respective maximum positions in the opened and closed state, if onone side of the switching film a control pressure is applied that doesnot equal an atmospheric pressure and/or a mechanical actuating means isprovided to switch the switching film.

Via a spring element, which is supported against the at least onehousing section, a force is applied to the switching film in order to beable to adjust the control response of the unit. For this purpose, thedischarge can have a valve seat arranged at an end in the housingsection, which is sealable by the sealing region of the switching film,whereby a discharge of fluid from the inlet to the discharge can beregulated. The spring element in this arrangement exerts the appropriatecounterforce on the switching film to achieve a control response of theunit in the desired pressure region. The side of the switching filmfacing away from the fluid to be regulated is generally supplied herewith atmospheric pressure.

According to the invention, a hole cross-section of the at least onehousing section of the unit is closed off by an operating region of theswitching film. In this manner the through-flow of the unit can beregulated, released, shut off or limited. An edge region surrounding theoperating region of the switching film allows a fluid-tight connectionof the switching film made from a polymer having fluorine and carbon, inparticular a thermoplastic having fluorine and carbon, against thehousing of the unit, which can be advantageously made from plastic, forexample, glass-fiber reinforced polyamide (PA), and represents anadditional great advantage over the prior art, in which the impermeableor closed membranes have no claim to tightness, rather, they are onlyinterlockingly connected to the housing. By virtue of the fluid-tightconnection, a region of the unit is advantageously guaranteed to besealed as fluid-tight, for example as a pressure regulation valve,because the switching film can in each case seal a housing sectionfluid-tight by being connected to the housing section, as well assealing of the interior spaces of two housing sections against eachother, if the first housing section is sealed with a second housingsection, such as with a housing cover.

According to one advantageous embodiment, at least one circumferentialmating surface can be provided situated radially to the outside on theat least one housing section at which the switching film is connected,in particular fixedly connected, in particular is fixedly andfluid-tightly connected to the at least one housing section. Throughthe, in particular fixed, connection of the switching film to the outerradially circumferential mating surface, the central inner region of theswitching film can move freely as a whole in the axial direction and asa sealing region of the switching film can thus exercise the actualswitching function of the unit, for example as pressure regulationvalve. Through the fluid-tight connection of the switching film againstat least one housing section, it can also be effectively prevented thatpossible outgassing of the material into the environment.

According to one advantageous embodiment, a radially outwardly situatedjoining region of the switching film has at least one connecting elementon at least one side facing the mating surface that can be connected, inparticular integrally and/or interlockingly bonded, welded, or pressedonto the at least one housing section. An inparticular integral and/orinterlocking connection of the connecting element of the switching filmwith the mating surface of the housing section can ensure thefluid-tight seal of the hole cross-section of the housing section aswell as the fixed and durable connection of the switching film for asafe function during the operating mode of the unit. The adhesive forthe connection of the connecting element to the mating surface can be,for example, common adhesives such as liquid silicones, acrylic-basedadhesives, formic acid, two-component adhesives. In the alternative,welding methods such as laser welding, ultrasound welding, mirror-imagedwelding or similar methods may be used.

According to one advantageous embodiment, the connecting element may beformed from plastic. Advantageously, the connecting element may enclosethe joining region of the switching film on both sides through theinjection or injection-molding with plastic and/or radially outwardlyenclose or respectively finish it. Thus, the joining region may beadvantageously be embedded in the connecting element with its radialouter edge. This way, a fixed and permanent connection can be achievedbetween the switching film and the connecting element. Alternatively,thermoplastically processable polytetrafluoroethylene may be molded tothe connecting element as switching film.

According to one advantageous embodiment, the switching film can, atleast in the region of the joining region, have at least one activatedsurface, in particular at least one activated surface directed toward afirst chamber of the first housing section. For preparation of theencapsulation with plastic, it can be advantageous to accordinglyprepare the surface of the switching film in that region where it comesinto contact with the plastic in order to change the surface tension.Such an activation can thus expediently include one or more methods suchas etching, plasma treatment, mechanical roughening, stamping,perforating or similar, appropriate methods. The contact between theplastic and the switching film can thereby be improved. In particular,it is advantageous to subject a surface of the switching film that isexposed to the fluid, such as is the case in the first chamber of thefirst housing section, to a treatment by activation.

According to one advantageous embodiment, the mating surface of the atleast one housing section can be formed to be self-adjusting in alongitudinal direction. In particular, the mating surface can be formedconically or curved upwards or downwards or corrugated.

By virtue of the self-adjusting mating surface, a particularly goodconnection of a different housing section as well as of the switchingfilm can be ensured with automatic centering of the first housingsection or of the switching film before and during the process of theconnection.

According to one advantageous embodiment, at least one radiallycircumferential groove can be provided radially inside the matingsurface of the at least one housing section and radially delimited onthe inside by an edge for supporting the switching film when there areaxial movements transverse to the hole cross-section, wherein inparticular two axial opposing and/or radially offset grooves can beprovided with an edge, in particular a raised lip. A raised lip on theedge advantageously supports dynamic movements of the switching filmwith its working region during the execution of the function in thepressure valve and simultaneously achieves a protection against damageby the motion of the switching film. The switching film is therebyalways located on at least one edge, preferably however at two edgessimultaneously during its switching motion. In order to prevent a damageto the switching film during the joining process such as, for example,by an unacceptable compression of the switching film by the edges, theedges can be arranged radially offset. A realization of a connection isthus easier, in that the switching film is located on two edgessimultaneously. A movement on the boundary surface to an edge can thenbe prevented. The edge can be optimized for the film motion so that theswitching film in operation is protected against damage by the edge. Itis also possible to apply a prestress of the switching film via theseedges.

According to one advantageous embodiment, a housing can be provided withthe first housing section and a second housing section, and the firstchamber can be separated fluid-tight from a second chamber by theswitching film. In this way, the second chamber of the unit can besupplied with an atmospheric pressure. For an effective control responseof the unit, the switching film should be able to move as freely aspossible, for which reason the second chamber, which is separated by theswitching film from the first chamber, in which the fluid to becontrolled is located, is expediently connected with the surroundingregion, meaning with the atmospheric pressure.

According to one advantageous embodiment, the polymer material havingfluorine and carbon is polytetrafluoroethylene orpolytetrafluoroethylene with admixtures or thermoplastically processablepolytetrafluoroethylene.

According to another aspect of the invention, a method for thefluid-tight connection of a switching film to at least one housingsection of a housing of a unit is proposed, wherein the switching filmis formed from a polymer material having fluorine and carbon, inparticular a thermoplastic having fluorine and carbon, and wherein ajoining region of the switching film situated radially to the outsidehas a connecting element on at least one side facing a mating surface ofthe at least one housing section that is connected in the region of atleast the mating surface to the at least one housing section, inparticular integrally and/or interlockingly bonded, welded, or pressedon. This method comprises the attaching of the connecting element in theregion of the joining region of the switching film, followed by aplacing of the switching film with the connection element on the matingsurface of the at least one housing section and the connection to thehousing section. After compressing the connecting element of theswitching film with the housing section, a durable and fluid-tightconnection of the switching film against the housing section and thus afluid-tight sealing of the hole cross-section of the housing section canthus be achieved.

According to one advantageous embodiment, the connecting element may beformed from plastic and advantageously formed by encapsulating theswitching film, in particular through a plastic encapsulation. Here, theconnecting element may advantageously be formed in a way that itencloses the joining region on both sides and/or radially to theoutside. Thus, the joining region may be advantageously be embedded inthe connecting element with its radial outer edge. This way, a fixed andpermanent connection can be achieved between the switching film and theconnecting element.

According to an alternative advantageous embodiment, thermoplasticallyprocessable polytetrafluoroethylene may be molded to the connectingelement as switching film. This way as well, an advantageous fixed andpermanent connection can be achieved between the switching film and theconnecting element.

According to one advantageous embodiment, the joining region of theswitching film is pretreated by at least one of the methods, etching,plasma treatment, mechanical grinding, embossing or perforation. Forpretreatment of the plastic encapsulation, it is advantageous toaccordingly pretreat and activate the surface of the switching film inthe region where it comes into connection with the plastic, which can beachieved with one of the procedures mentioned. In this way the surfacetension can be changed, whereby the contact between the plastic and theswitching film can be essentially improved.

Advantageously, a second housing section can advantageously be placed onthe switching film after the placement of the switching film on the atleast one first housing section with the connecting element over themating surface, thus forming the housing. At the same time, the secondhousing section can also be expediently bonded or welded to theconnecting element of the switching film and/or to the first housingsection. Alternatively, it is also conceivable to radially weld the twohousing sections, which can be formed from, for example, glass-fiberreinforced polyamide (PA), outside the switching film.

Expediently, the connecting element of the switching film can becompressed when the housing is sealed in the region of the matingsurface. By the compression, for example, a greater final strength ofthe connection can be achieved. In this way, the fluid-tight connectioncan also be favorably improved.

Advantageously, the switching film can be axially supported by at leastone groove running radially inside the mating surface in the at leastone housing section, which is radially delimited inside by a lip, inparticular a raised lip, for supporting the switching film during axialmovements transverse to its cross-sectional area. In this way, dynamicmovements of the switching film during the execution of the function inthe pressure regulating valve can be advantageously supported and, atthe same time, a protection against damage by the movement of theswitching film can be achieved. The switching film is thereby alwayslocated on at least one edge, preferably however at two edgessimultaneously during its switching motion. In order to prevent a damageto the switching film during the joining process such as, for example,by an unacceptable compression of the switching film by the edges, theedges can be arranged radially offset. A realization of a connection isthus easier, in that the switching film is located on two edgessimultaneously. A movement on the boundary surface to an edge can thenbe prevented. The edge can be optimized for the film movement so thatthe switching film is protected against damages by the edge duringoperating mode.

Advantageously, the switching film can also be axially supported by twogrooves arranged in the housing with an edge, which are arrangedopposite each other or radially displaced relative to each other. Inthis further embodiment, the edges of the housing section can bemutually shifted so that the switching film is not crimped in thisregion during the joining process. It is also possible to adjust thepretension of the switching film via these edges.

In an expedient manner, the housing can also be sealed at a radial outercircumference after the application of the switching film to theconnecting element through a bonding or welding process. Additionally,the housing section, in which the hole cross-section is closedfluid-tight by the switching film, can in this way be firmly bonded orwelded to another housing section, for example a cover, or the housingsection can be bonded or welded to a different component. In thismanner, a further fluid-tight sealing of the unit for safe operation,for example as a pressure regulating valve, can be achieved. The matingsurface for the welding or bonding can thus expediently be designed sothat the welding beads or adhesive beads from the welding process do notadversely affect the connection of the housing section and theconnection of the switching film with the housing components.

According to a further aspect of the invention, the unit according tothe invention is used for pressure regulation of an internal combustionengine and/or for pressure regulation of a crankcase of an internalcombustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages arise from the following drawing description.Embodiments of the invention are illustrated in the drawings. Thedrawings, the description and the claims contain numerous features incombination. A person skilled in the art will also expediently considerthe features on an individual basis and combine them into otherappropriate combinations.

Shown by way of example are:

FIG. 1 a unit having a switching film made from a polymer with fluorineand carbon according to an exemplary embodiment of the invention in asectional view;

FIG. 2 a unit having a switching film according to an additionalexemplary embodiment of the invention in a sectional view;

FIG. 3 a unit having a plastic encapsulation of the switching film asconnecting element according to a next exemplary embodiment of theinvention in a sectional view;

FIG. 4 a simplified detail of the joining region of a version of theunit from FIG. 3 in a sectional view without second housing section; and

FIG. 5 a detail of the unit's joining region from FIG. 3 in a sectionalview;

DETAILED DESCRIPTION

The same or similar components in the figures are referenced with samereference characters. The figures merely show examples and are notintended to be restrictive.

FIG. 1 shows a sectional view of a unit 10 for the regulation or controlof a fluid pressure using a switching film 22 made from a polymer havingfluorine and carbon according to an exemplary embodiment of theinvention. The polymer material having fluorine and carbon is thuspolytetrafluoroethylene or polytetrafluoroethylene with admixtures orthermoplastically processable polytetrafluoroethylene particularly in aspraying process. The unit 10 serves for regulation or control of afluid pressure, in particular for application for pressure regulation ofan internal combustion engine and/or for the pressure regulation of acrankcase of an internal combustion engine. The unit 10 has a housing 12having a first housing section 13 and a second housing section 14, thehousing cover, wherein the first housing section 13 has an inlet 28 anda discharge 30 for the fluid. The switching film 22 is formed from apolymer film having fluorine and carbon, for example PTFE, and isclamped with a joining region 42 between first housing section 13 andthe second housing section 14.

The hole cross-section 40 of the two housing sections 13, 14 isfluid-tightly sealed by the switching film 22 with its functionalregion. Two circumferential mating surfaces 50, 52 are fluid-tightlyprovided situated radially to the outside on the two housing sections13, 14, at which the switching film 22 is connected to the two housingsections 13, 14, in particular fixed and fluid-tight. In the shownexemplary embodiment, a radially outwardly situated joining region 42 ofthe switching film 22 has at least one thin connecting element 44 on atleast one side facing the mating surface 50, 52 that is connected, inparticular integrally and/or interlockingly bonded, welded, or pressedto the at least one housing section 13, 14. The connecting element 44may be formed from plastic and may, in particular, be formed throughinjection-molding at the mating surface 42. Alternatively, the switchingfilm 22 may be injection-molded to the connection element 44 as well.The connecting element 44 may in particular be formed in a way that itencloses the joining region 42 on both sides and/or radially on theoutside. In the exemplary embodiments in FIGS. 1 and 2, the connectingelement 44 is shown in a diagram. Details are shown in FIGS. 3 to 5.

The switching film 22 separates a first chamber 36 of the unit 10 from asecond chamber 38 in a fluid-tight manner. There is a pressuredifferential between the first chamber 36 and the second chamber 38,wherein the second chamber 38 is connected (not depicted) to thesurrounding space, meaning to the atmosphere. The switching film 22 canbe moved with pressure differences of 1 to 250 mbar, preferably from 1to 100 mbar, and serves to release or shut off a through-flow of thefluid between the inlet 28 and the discharge 30. The inlet 28 of theunit 10 is fluidically connected during use to, for example, thecrankcase of an internal combustion engine, while the discharge 30 isfluidically connected to the breather line. The switching film 22 has aplate-like flat body 16 having a corrugated bending region 18surrounding a central sealing region 24. The bending region 18 movesduring switching of the switching film 22 by a low-strain, in particularstrain-free bending motion of the sealing region 24 with respect to avalve seat 32 in an axial direction L toward the valve seat 32 or awayfrom the valve seat 32. For this, the switching film 22 has at least inthe bending region 18 a thickness of at most 0.5 mm, preferably of atmost 0.3 mm, most preferably of at most 0.2 mm. The diameter of theswitching film 22 can thus be between 40 mm and 100 mm, preferablybetween 50 mm and 80 mm.

The bending region 18 extends in a wave-like manner in radial directionaround sealing region 24, wherein a recess on a flat side corresponds toan elevation on the other flat side of the switching film 22. Thesealing region 24 seals the valve seat 32 if it is located on the valveseat 32. A spring element 26 is provided that is supported at the firsthousing section 13 which exerts a force on the sealing region 24 of theswitching film 22. The spring element 26 is supported here by anannularly formed plate 34 at the sealing region 24. The sealing region24 is formed as a bowl-shaped projection 20 of the switching film 22,wherein the plate 34 in the form of a support ring annularly enclosesthis projection. The spring element 26 can alternatively engage theswitching film 22 without plate 34 and thus be sprayed on its end facethat is turned towards the projection 20 for protection of the switchingfilm 22, so that the encapsulation can replace the plate 34.

A groove 54, 56 running radially is provided inside the mating surface50, 52 of each of the two housing sections 13, 14, which is delimitedradially inside by an edge 58, 60 for supporting the switching film 22during axial movements transverse to the hole cross-section 40. The twogrooves 54, 56 are located axially opposite one another. Because theswitching film 22 is located on the rounded edges 58, 60 and is clampedbetween them, the switching film 22 is protected against excessive wearand damages from sharp edges resulting from axial movements of itsworking region because of the regulating function of the unit 10.

FIG. 2 shows in a cross-sectional view a unit 10 having a switching film22 according to an additional exemplary embodiment of the invention. Thebasic design of the unit 10 essentially corresponds to the exemplaryembodiment in FIG. 1. The mating surfaces 50, 52 of the two housingsections 13, 14, however, are formed conically in the longitudinaldirection L. In this manner, the switching film 22 can advantageously becentered during the joining of the switching film 22 at the firsthousing section 13 and during assembly of the housing 12 by placement ofthe second housing section 14. The grooves 54, 56 with their edges 58,60—in contrast to the embodiment in FIG. 1 where they are arrangedaxially opposed—are arranged in this case radially displaced, which canalso be beneficial for the support of the switching film 22 during theaxial movement of the switching film 22.

FIG. 3 shows a unit 10 having a plastic encapsulation of the switchingfilm 22 as the connecting element 44 according to a next exemplaryembodiment of the invention in a sectional view. The spring element 26was left out to provide greater clarity. FIGS. 4 and 5 both show adetail of the housing 12 of unit 10 from FIG. 3 with the joining region42 or, respectively, a simplified detail of the housing 12.

In comparison with the two exemplary embodiments in FIGS. 1 and 2, theunit 10 in FIG. 3 does not have any grooves 54, 56 with raised lips 58,60 to relieve the switching film 22 in the pending motions. Theswitching film 22 with the connecting element 44 is mounted between thetwo housing sections 13, 14 and can be integrally bonded or welded.Welding methods such as laser welding, ultrasound welding, mirror-imagedwelding or similar methods may be used here.

A radially outward joining region 42 of the switching film 22 thuscomprises a connecting element 44 enclosing the joining region 42, whichcan be integrally and/or interlockingly connected to the two housingsections 13, 14 in the area of the mating surfaces 50, 52, and inparticular bonded or welded. Here, the connecting element 44 is attachedin the are of the joining region 42 of the switching film 22. Then, theswitching film 22 having the connecting element 44 is placed on themating surface 50, 52 of a housing section 13, 14 and the connectingelement 44 connected with the housing section 13, 14. Then, the secondof the housing sections 14, 13 can be place and integrally connectedwith the connecting element 44. The connecting element is advantageouslyformed by encapsulating the joining region 42 with plastic and canenclose the joining region 42 at both sides and at the radial outside.The bonding may be, for example, common adhesives such as liquidsilicones, acrylic-based adhesives or two-component adhesives. Thewelding method to be used may be laser welding or ultrasound welding.Advantageously, the switching film 22 in this arrangement, at least inthe region of the joining region 42, may have an activated surface withaltered surface tension in order to achieve a good plasticencapsulation, wherein the joining region 42 is prepared, for example,by one of the methods, etching, plasma treatment, mechanical roughening,embossing or perforation. The housing 12 is preferably sealed to aradial outer circumference after the insertion of the switching film 22through the connecting element 44 by welding.

The simplified detail of the joining region 42 of unit 10 in FIG. 4shows how the switching film 22 is embedded in the connecting 44 throughplastic encapsulation and how, together with the connection element 44,it lies flat on the mating surface 50 of the housing section 13. This ishow the connecting element 44 can be bonded to the mating surface 50 orwelded to the mating surface 50. In this exemplary embodiment, a secondhousing section may be provided which covers the switching film 22.

FIG. 5 shows how, after the second housing section 14 has been placed onthe connecting element 44, the housing 12 can be sealed by placing thehousing section 14 with its mating surface 52 on the connecting element44 and integrally connecting it with this element, in particular throughbonding or welding. In this way, the housing 12 can be sealed in afluid-tight manner.

What is claimed is:
 1. A regulation unit for the regulation or controlof a fluid pressure, comprising: a regulation housing having: a firsthousing section and a second housing section; a fluid inlet port; afluid discharge port; a switching film connected to the at least onehousing section and adapted to switch at pressure differentials of 1 to250 mbar relative to an ambient pressure acting on the switching film,the switching film deflecting in an axial direction from an openposition to a closed position; wherein a radial direction, as usedherein, is a direction transverse the axial direction; wherein theswitching film has a joining region situated proximate to a radiallyouter edge of the switching film; wherein the switching film is adaptedfor regulation, release or blocking of a flow of the fluid between theinlet port and the fluid discharge port; wherein the switching film is apolytetrafluoroethylene (PTFE) film having a thickness at most of 0.5mm, an annular connecting element of a plastic material, the annularconnecting element arranged on and fixed onto the joining region;wherein the first housing section has a first chamber, wherein thesecond housing section has a second chamber, wherein the first housingsection and the second housing section each have a hole through whichthe first chamber opens into the second chamber of the second housingsection, the first and the second housing section holes having a holecross-section; wherein the first housing section and the second housingsection each have a circumferential mating surface situated radially tothe outside and radially surrounding the hole cross-section; wherein thecircumferential mating surfaces of the first and second housing sectionsare adapted to align for mating; wherein the circumferential matingsurfaces of the two housing sections are formed as two parallel conicalmating surfaces, the two parallel conical surfaces extending directly onthe joining region and spaced apart by a thickness of the switching filmin the joining region, the two parallel conical mating surfaces therebyproviding automatic centering alignment of the circumferential matingsurfaces while mating the housing sections; wherein the annularconnecting element fixes the joining region of the switching film ontothe circumferential mating surface of at least one of the housingsections; wherein the hole cross-section of the first and second housingsections is closed off by the switching film; the regulation unitfurther comprising: a first circumferential groove formed in thecircumferential mating surface of the first housing section; a secondcircumferential groove formed in the circumferential mating surface ofthe second housing section; wherein the first housing section has afirst circumferential edge projection forming a radially inner wall ofthe first circumferential groove, the first circumferential edgeprojection projecting outwardly, contacting against and supporting theswitching film when there are axial movements transverse to the holecross-section; wherein the second housing section has a secondcircumferential edge projection forming a radially inner wall of thesecond circumferential groove, the second circumferential edgeprojection projecting outwardly, contacting against and supporting theswitching film when there are axial movements transverse to the holecross-section; wherein the circumferential edge projection of a firstone of the housing sections is spaced radially inwardly away from thecircumferential edge projection of a second one of the housing sections.2. The regulation unit according to claim 1, wherein the circumferentialmating surfaces are situated radially to the outside of the holecross-section and radially surrounding the hole cross-section; whereinthe switching film is fixedly and fluid-tightly connected to thecircumferential mating surface of at least one of the housing sectionsand closing off the hole cross-section.
 3. The regulation unit accordingto claim 2, wherein the annular connecting element is integrally and/orinterlockingly connected to the circumferential mating surface of atleast one of the housing sections.
 4. The regulation unit according toclaim 3, wherein the annular connecting element of the plastic materialis formed through injection molding onto the circumferential matingsurface.
 5. The regulation unit according to claim 3, wherein theannular connecting element radially encloses the joining region on bothsides of the switching film and the radially outer edge of the switchingfilm.
 6. The regulation unit according to claim 1, wherein thepolytetrafluoroethylene (PTFE) film, at least in the region of thejoining region, has at least one activated surface formed directly onthe polytetrafluoroethylene (PTFE) that is directed toward the firstchamber of the first housing section, wherein the activated surface is aplasma treated surface, or mechanically roughened surface, or hasperforations, such that the activated surface improves contact andbonding to the annular connecting element.
 7. The regulation unitaccording to claim 1, wherein the polytetrafluoroethylene (PTFE) of theswitching film is: a polytetrafluoroethylene with admixtures, or athermoplastically processable polytetrafluoroethylene.
 8. A method offorming a fluid-tight connection of a switching film onto at least onehousing section of the regulator housing of the regulation unitaccording to claim 1, comprising the steps of: providing the switchingfilm of polytetrafluoroethylene (PTFE) having a thickness at most of 0.5mm; wherein the joining region of the switching film is situatedproximate to the radially outer edge of the switching film; providingthe first housing section having the first chamber, the first chambersurrounded by the circumferential mating surface of the first housingsection, the first housing section having a first circumferential grooveformed in the circumferential mating surface of the first housingsection, the first housing section having a first circumferential edgeprojection forming a radially inner wall of the first circumferentialgroove, the first circumferential edge projection projecting outwardly,contacting against and supporting the switching film when there areaxial movements transverse to the hole cross-section; providing thesecond housing section having the second chamber, the second chambersurrounded by the circumferential mating surface of the second housingsection, the second housing section having a second circumferentialgroove formed in the circumferential mating surface of the secondhousing section, the second housing section having a secondcircumferential edge projection forming a radially inner wall of thesecond circumferential groove, the second circumferential edgeprojection projecting outwardly, contacting against and supporting theswitching film when there are axial movements transverse to the holecross-section; wherein the circumferential mating surfaces of the firstand second housing sections are adapted to align for mating; wherein thecircumferential mating surfaces of the two housing sections are formedas two parallel conical mating surfaces when in an assembled state;pretreating the joining region of the switching film by at least one ofthe methods: plasma treatment, embossing or perforation; providing theconnecting element of a plastic material; applying the connectingelement to the switching film at the joining region; placing theswitching film onto the circumferential mating surface of the firsthousing section; integrally and/or interlockingly bonding the firsthousing section to the switching film; mating the housing sections whileautomatically centering the two parallel conical mating surfaces ofhousing sections directly on the joining region and spaced apart by athickness of the switching film in the joining region.
 9. The methodaccording to claim 8, wherein the annular connecting element of theplastic material is formed onto the polytetrafluoroethylene (PTFE) ofthe switching film by encapsulating the switching film through injectionmolding such that a radial outer edge of the switching film isencapsulated into an interior of the connecting element.
 10. The methodaccording to claim 9, wherein the switching film is molded onto theconnecting element.